Open AccessEnhancements of lobe ion density and velocity associated with plasmoids
Author(s) -
Shirai H.,
Takada T. K.,
Kamide Y.,
Mukai T.
Publication year - 2001
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2001ja900086
Subject(s) - plasmoid , ion , physics , substorm , spacecraft , astrophysics , atomic physics , geophysics , plasma , geodesy , geology , magnetic reconnection , astronomy , magnetosphere , nuclear physics , quantum mechanics
Intermittent enhancements of lobe ions in density and velocity were observed by the GEOTAIL spacecraft in the distant magnetotail (∼100–200 R E ). They were observed after the passage of plasmoids, accompanying south‐to‐north bipolar variations in Bz , which are opposite in polarity to those observed with plasmoids or traveling compression regions. The peaks in the ion density occurred when Bz changed from south to north (i.e., when Bz = 0). To explain these observations, a model is presented in which the magnetotail shrinks behind a plasmoid. It is suggested that after the formation of a plasmoid the near‐Earth neutral line runs tailward following the plasmoid. The delay between the plasmoid passage and the ion enhancement observed by the same spacecraft is ∼5–70 min, depending on as yet unknown reasons.